Methane-derived authigenic carbonates – A case for a globally relevant marine carbonate factory

Quantifying the Extent of Authigenic Carbonate Formation in Shallow Marine Sediments Through a Correlation Between Carbonate Precipitation Rate and Sulfate Flux

“…(2020), and the updated 2.28 Tmol a −1 of Akam et al. (2023), but is much higher than the 0.14 Tmol a −1 estimated by Bradbury and Turchyn (2019). The latter much lower estimate (0.14 Tmol a −1 ) has been attributed to neglecting non‐IODP sites and AC production from Mg 2+ flux at IODP sites (Akam et al., 2020).…”

“…If such a close linkage could be projected to the global scale, AC production at and above the SMTZs in marine sediments affected by methane diffusion would be 2.2-2.3 Tmol a −1 based on the revised global 𝐴𝐴 SO4 2− flux (7.5-8.0 Tmol a −1 ; Hu et al, 2023). Such an estimate is close to 1 Tmol a −1 estimated by Sun and Turchyn (2014), 1.7 Tmol a −1 calculated by Akam et al (2020), and the updated 2.28 Tmol a −1 of Akam et al (2023), but is much higher than the 0.14 Tmol a −1 estimated by Bradbury and Turchyn (2019). The latter much lower estimate (0.14 Tmol a −1 ) has been attributed to neglecting non-IODP sites and AC production from Mg 2+ flux at IODP sites (Akam et al, 2020).…”

“…Recent efforts have been made to quantify the extent of authigenic carbonate formation in modern marine shallow sediments (Akam et al., 2020, 2023; Bradbury & Turchyn, 2019; Sun & Turchyn, 2014). However, estimates on the extent of authigenic carbonate formation in the modern ocean vary greatly, ranging from 0.14 Tmol a −1 based on a machine learning approach using the IODP database (Bradbury & Turchyn, 2019) to 1 Tmol a −1 based on a spatial interpolation approach using the IODP database (Sun & Turchyn, 2014), and 1.7–2.28 Tmol a −1 based on compiled sulfate fluxes and related data from the literature (Akam et al., 2020, 2023).…”

“…Recent efforts have been made to quantify the extent of authigenic carbonate formation in modern marine shallow sediments (Akam et al., 2020, 2023; Bradbury & Turchyn, 2019; Sun & Turchyn, 2014). However, estimates on the extent of authigenic carbonate formation in the modern ocean vary greatly, ranging from 0.14 Tmol a −1 based on a machine learning approach using the IODP database (Bradbury & Turchyn, 2019) to 1 Tmol a −1 based on a spatial interpolation approach using the IODP database (Sun & Turchyn, 2014), and 1.7–2.28 Tmol a −1 based on compiled sulfate fluxes and related data from the literature (Akam et al., 2020, 2023). The latter estimate has considered magnesium consumption by authigenic carbonate formation and incorporated sites from non‐IODP databases (Akam et al., 2020); this approach relied on a limited data set of compiled proportions of pore‐water DIC transferred into authigenic carbonates to estimate the amount of authigenic carbonate formation.…”

Resolving and correcting for kinetic biases on methane seep paleotemperature using carbonate ∆ 47 /∆ 48 analysis

“…Carbonate minerals are an abundant by-product of sulfate-driven anaerobic oxidation of methane (SD-AOM) ( 18 ), and mineralization rates are greatest in regions where sulfate and methane react [sulfate-methane transition zone (SMTZ); Fig. 1 ].…”